1. Field of the Invention
The invention relates to the field of semiconductor manufacturing technology, more particularly, to a method for preparing three-dimensional integrated inductor-capacitor structure.
2. Description of the Related Art
With advances of science and technology and improvement of the degree of social information, More and more technical areas such as computer and communication are using radio frequency technology, radio frequency technology promotes rapid development of radio-frequency technique (RFIC), for the requirement of high frequency, low-power, low distortion of radio-frequency technique, inductance coil becomes necessary. The inductance coil is by the wire winding on the wire frame, wire is isolated each other, while winding can be hollow or core may be comprised, which is called inductor for short. The inductance is mainly used for segregating and filtering AC signal, or comprising a resonant circuit with capacitors and resistors.
The most important indicators to evaluating the performance of the inductance is the quality factor Q, the quality factor Q (the value of Q) represents the ratio of the stored energy and the energy dissipation per cycle in a storage device (such as inductors, capacitors, etc.), and a resonance circuit, thereby the performance indicators of integrated inductor can be increased via increasing the quality factor Q of inductance.
Most of the flat structure integrated inductors in prior art, because of the production in the parallel plane of the substrate, eddy current may form in the substrate at high frequencies, and the direction of the eddy current is opposite to the direction of the current in the inductance coil, which will inevitably lead to the decrease of magnetic flux of inductance coil, and biggish additional energy loss and make the Q value of whole inductance declined. What's more, in prior art, the integrated inductor is difficult to achieve high inductance value and high quality factor Q due to limitations of manufacture procedure and materials of integrated circuit, and the circuit configuration with both inductor and capacitor is necessary to increase the area of the device, which increases production costs to a certain extent.
The prior art to solve the problem of eddy current in the substrate by reducing the loss of the substrate, but using planar structure integrated inductors cannot increase the inductance magnetic flux in order to increase the inductance value and reduce eddy current and improve the quality factor Q value at the same time, this is because of the limitations of operating principle of the planar inductor cannot solve the problem fundamentally. Thus, inventing a high-performance integrated inductor and capacitor elements becomes a problem in the field of semiconductor manufacturing technology.